Solid fuel burner, combustion apparatus using solid fuel burner, and method of operating the combustion apparatus

Abstract

An air nozzle provided on the outer side of a fuel nozzle of a solid fuel burner is divided into a plurality of regions, and has means for regulating air flow rates in nozzles divided in the upper and lower direction. The nozzles (regions) are connected to only the nozzle wall and have obstacles in the circumferential direction, dividing the inside of the nozzle into a plurality of regions, and by changing air flow rates in the respective regions in the outermost peripheral air nozzle, a deviation in momentum is caused in the vertical direction of the burner, a flame forming position is changed, and a combustion gas temperature at the furnace outlet, temperatures of a heat transfer tube installed on the furnace wall surface and a fluid flowing in the heat transfer tube or temperatures of heat transfer tubes provided in the furnace and a flue on the downstream side and temperatures of fluids flowing in the heat transfer tubes are controlled to be constant.

1 . A solid fuel burner comprising: a fuel nozzle which ejects a mixture fluid of a solid fuel and a conveying gas; and at least one air nozzle which is disposed on the outer side of the fuel nozzle and ejects combustion air, wherein
 at least one air nozzle is formed to be annular on the outer periphery of the fuel nozzle, and the internal air passage of the annular air nozzle is divided into a plurality of regions in the circumferential direction of the annular air nozzle by an obstacle, and the solid fuel burner has means of regulating a flow rate for regulating an air flow rate flowing in at least one of the plurality of divided regions.   
     
     
         2 . The solid fuel burner according to  claim 1 , wherein obstacles for dividing the internal air passage of the annular air nozzle into a plurality of regions in the circumferential direction of the air nozzle are, (a) obstacles connected to only an inner peripheral side partition wall constituting the air nozzle, (b) obstacles connected to only an outer peripheral side partition wall of the air nozzle, or (c) double obstacles formed by combining an obstacle connected to only the inner peripheral side partition wall and obstacles connected to only the outer peripheral side partition wall. 
     
     
         3 . The solid fuel burner according to  claim 1 , wherein
 a sectional shape in a direction across a passage on the outlet side of the fuel nozzle is relatively short in length in one radial direction of the fuel nozzle and relatively long in length in a radial direction orthogonal to the one radial direction, and   an inner peripheral partition wall constituting at least one air passage in the air nozzles has a sectional shape in a direction across the air passage which is relatively short in length in one radial direction of the air nozzle and relatively long in length in a radial direction orthogonal to the one radial direction, and an outer peripheral partition wall is equal in length in one radial direction and in a radial direction orthogonal to the one radial direction.   
     
     
         4 . The solid fuel burner according to  claim 3 , wherein the sides of which the lengths in one radial direction of the fuel nozzle and the air nozzle are relatively short are formed in the vertical direction, and the sides of which the lengths in a radial direction orthogonal to the one direction are relatively long are formed in the horizontal direction. 
     
     
         5 . The solid fuel burner according to  claim 1 , comprising: in addition to the annular air nozzle, an air nozzle disposed on the outer side of the annular air nozzle; and means of regulating a flow rate for regulating an air volume to be ejected from the air nozzle disposed on the outer side of the annular air nozzle. 
     
     
         6 . The solid fuel burner according to  claim 5 , wherein obstacles which divide the inside of the annular air nozzle into a plurality of regions in the circumferential direction of the air nozzle are connected to the outer wall surface of the fuel nozzle. 
     
     
         7 . The solid fuel burner according to  claim 5 , wherein a part of the air nozzle divided into the plurality of regions provided on the outer periphery of the air nozzle formed annularly on the outer periphery of the fuel nozzle has air passages only on the upper side and the lower side of the fuel nozzle, and the air passage includes an obstacle connected to only the inner peripheral side partition wall of the air passage, and the obstacle forms a closed space opened at only inlet and outlet of combustion air flow direction. 
     
     
         8 . The solid fuel burner according to  claim 1 , wherein at an outlet of at least one air nozzle of the air nozzles, guide members which deflect an air flow to the outer peripheral side direction of the air nozzle away from the fuel nozzle are provided. 
     
     
         9 . The solid fuel burner according to  claim 1 , wherein at an outlet of the fuel nozzle, obstacles which obstruct a fuel jet flow flowing in the fuel nozzle or an air flow flowing in the air nozzle close to the fuel nozzle are provided. 
     
     
         10 . A combustion apparatus comprising a furnace having the solid fuel burner according to  claim 1  installed on a furnace wall, wherein
 the combustion apparatus includes a control device which changes an air flow rate flowing in at least one of the plurality of regions of the air nozzle of the solid fuel burner, whose inside is divided by obstacles in the circumferential direction of the fuel nozzle into the plurality of regions, based on a combustion gas temperature at the furnace outlet, a temperature of a heat transfer tube installed on a furnace wall surface, a temperature of a fluid flowing in the heat transfer tube, temperatures of heat transfer tubes provided in the furnace and a flue on the downstream side of the furnace or temperatures of fluids flowing in the heat transfer tubes. 
 
     
     
         11 . A method of operating a combustion apparatus comprising a furnace including the solid fuel burner according to  claim 1  installed on a furnace wall, wherein
 a deviation is generated in the circumferential direction of the fuel nozzle in an air volume flowing in the air nozzle of the solid fuel burner based on a combustion gas temperature at the furnace outlet, temperatures of heat transfer tubes installed on a furnace wall surface, a temperature of a fluid flowing in the heat transfer tube, temperatures of heat transfer tubes provided in the furnace and a flue on the downstream side of the furnace or temperatures of fluids flowing in the heat transfer tubes. 
 
     
     
         12 . The solid fuel burner according to  claim 2 , wherein
 a sectional shape in a direction across a passage on the outlet side of the fuel nozzle is relatively short in length in one radial direction of the fuel nozzle and relatively long in length in a radial direction orthogonal to the one radial direction, and   an inner peripheral partition wall constituting at least one air passage in the air nozzles has a sectional shape in a direction across the air passage which is relatively short in length in one radial direction of the air nozzle and relatively long in length in a radial direction orthogonal to the one radial direction, and an outer peripheral partition wall is equal in length in one radial direction and in a radial direction orthogonal to the one radial direction.   
     
     
         13 . The solid fuel burner according to  claim 12 , wherein the sides of which the lengths in one radial direction of the fuel nozzle and the air nozzle are relatively short are formed in the vertical direction, and the sides of which the lengths in a radial direction orthogonal to the one direction are relatively long are formed in the horizontal direction.